A methacrylic resin known as a thermoplastic resin is used as a raw material for vehicle members such as a tail lamp cover and a meter panel because of excellent transparency. Also, an aromatic polycarbonate resin is a thermoplastic resin excellent in transparency, heat resistance, and impact resistance, and therefore used as a raw material for vehicle members such as a headlamp cover.
For the tail lamps and headlamps of vehicles, an antifogging property for preventing fogging in a lamp is required. Conventionally, halogen lamps have been mainly used as tail lamps and headlamps, and the halogen lamps have provided a certain degree of antifogging effects by temperature rise of a lamp cover accompanying irradiation with an irradiation light from a light source. However, in recent years, LED lamps and semiconductor lasers are increasingly used as light sources for lamps, instead of conventional halogen lamps. However, these light sources cannot allow the temperature of the lamp cover to sufficiently rise when the lamp cover is irradiated with the radiation light. As a result, dew condensation is caused in the lamp cover, and the lamp cover tends to fog.
When such a light source giving low temperature rise of the lamp cover due to the irradiation of the light source is used, a lamp cover capable of absorbing heat rays such as sunlight to generate heat is required. A vehicle lamp equipped with a lamp cover comprising an infrared absorbent which satisfies such a request is known (Patent Document 1). It is described that such a vehicle lamp can provide an excellent antifogging property even without antifogging coating.